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United States Patent |
5,582,040
|
Khan
|
December 10, 1996
|
Water balancing apparatus for horizontal axis and vertical axis laundry
appliances
Abstract
A balancing apparatus for counterbalancing an unbalanced load in a rotating
or spinning drum such as a clothes basket in a washing machine. The
balancing apparatus includes a drive plate fixed to the drive shaft of the
spinning drum. Balancing tanks disposed at spaced intervals around the
drum are connected to a fluid supply, such, as a self contained fluid
tank, through passages controlled by valves mounted to the drum or supply
tank. When the rotating drum tilts relative to the drive shaft as a result
of unsymmetrical centrifugal forces produced by the unbalanced load, the
valve or valves controlling flow into the balance tanks opposite the
unbalanced load are moved into engagement with valve selector slides
mounted on the drive plate to open the passages and allow water from the
fluid tank into the balance tanks to balance the drum. The valves and
valve selector slides are preferably complementarily designed to permit
fluid flow into the balance tanks opposite the unbalanced load at drum
rotating speeds below and above the critical speed of the rotating drum.
Inventors:
|
Khan; Aman U. (1413 N. Manor Dr., St. Joseph, MI 49085)
|
Appl. No.:
|
513072 |
Filed:
|
August 9, 1995 |
Current U.S. Class: |
68/23.2; 68/23.3; 74/572.4; 210/144 |
Intern'l Class: |
D06F 037/22; D06F 037/24 |
Field of Search: |
68/12.06,23.2,23.3
210/144
74/573 F
|
References Cited
U.S. Patent Documents
1604748 | Oct., 1926 | Grauer | 210/144.
|
2224241 | Dec., 1940 | Verdier et al. | 74/573.
|
2463801 | Mar., 1949 | Page | 68/23.
|
2539533 | Jan., 1951 | Douglas | 68/23.
|
2886979 | May., 1959 | Baxter | 74/573.
|
3119773 | Jan., 1964 | Compans | 210/144.
|
3135688 | Jun., 1964 | Compans | 210/144.
|
3190447 | Jun., 1965 | Scott | 210/144.
|
3235082 | Feb., 1966 | Compans | 210/144.
|
3275146 | Sep., 1966 | Severance | 210/144.
|
3306453 | Feb., 1967 | Khan | 210/144.
|
3983035 | Sep., 1976 | Arkeveld | 68/23.
|
4991247 | Feb., 1991 | Castwall | 68/23.
|
5345792 | Sep., 1994 | Farrington | 68/23.
|
Primary Examiner: Coe; Philip R.
Attorney, Agent or Firm: Baker & Daniels
Claims
What is claimed is:
1. A balancing apparatus for a centrifugal extractor machine including a
rotatable drum mounted on a shaft, wherein the drum is tiltable relative
to the shaft whereby an axis of rotation of the drum is angled relative to
an axial direction in which the shaft extends, said balancing apparatus
comprising:
at least one valve actuator arranged around the shaft;
a plurality of balancing pockets disposed around the drum for receiving
fluid to counterbalance an unbalanced load in the rotatable drum tending
to tilt the drum during drum rotation;
a plurality of fluid passages for communicating fluid to said plurality of
balancing pockets;
at least one fluid supplier providing fluid to said plurality of fluid
passages; and
a plurality of valves controlling fluid flow through said plurality of
fluid passages, said plurality of valves each structured and arranged to
operatively engage said at least one valve actuator when said balancing
pocket to which its respective valve passage communicates moves a distance
toward said at least one valve actuator during drum tilting, wherein
engagement of each valve with said at least one valve actuator opens said
valve to allow fluid from said at least one fluid supplier to flow through
said fluid passage associated with the open valve and into said balancing
pocket associated with the open valve to counterbalance the unbalanced
load.
2. The balancing apparatus of claim 1 wherein said at least one fluid
supplier comprises a 360.degree. self contained fluid tank mounted for
rotation with the drum.
3. The balancing apparatus of claim 1 wherein said at least one fluid
supplier comprises a 360.degree. fluid supply ring, mounted for rotation
with the drum, and a conduit connected to a fluid source for introducing
fluid into said fluid supply ring.
4. In combination:
a laundry machine including a rotatable drum and a motor powered drive
shaft driving the rotation of said rotatable drum, wherein said drum is
tiltable relative to said drive shaft whereby an axis of rotation of said
drum is angled relative to an axial direction in which said drive shaft
extends; and
a balancing apparatus for counterbalancing an unbalanced load in said
rotatable drum, said balancing apparatus comprising:
at least one valve actuator corotatable with said drive shaft;
a plurality of balancing pockets disposed around the drum for receiving
fluid to counterbalance the unbalanced load in said rotatable drum tending
to tilt the drum during drum rotation;
a plurality of fluid passages for communicating fluid to said plurality of
balancing pockets;
at least one fluid supplier providing fluid to said plurality of fluid
passages; and
a plurality of valves controlling fluid flow through said plurality of
fluid passages, said plurality of valves each structured and arranged to
operatively engage said at least one valve actuator when said balancing
pocket to which its respective valve passage communicates moves a first
distance toward said at least one valve actuator during drum tilting,
wherein engagement of each valve with said at least one valve actuator
opens said valve to allow fluid from said at least one fluid supplier to
flow through said fluid passage and into said balancing pocket associated
with the open valve to counterbalance the unbalanced load.
5. The combination of claim 4 wherein said laundry machine further
comprises at least one resilient bushing between said rotatable drum and
said drive shaft allowing tilting motion therebetween.
6. The combination of claim 4 wherein said plurality of valves are each
pivotally mounted to said rotatable drum.
7. The combination of claim 4 wherein said at least one valve actuator
comprises at least one base member and a plurality of valve selector
slides mounted to said at least one base member in registry with said
plurality of valves, wherein each slide is shiftable between first and
second positions, wherein each said valve comprises a first actuating
member and a second actuating member, wherein each corresponding valve and
slide is complementarily configured such that said first actuating member
is engagable with said slide when said slide is disposed in said first
position and said balancing pocket associated with said valve moves said
first distance toward said at least one base member during drum tilting,
wherein said first actuating member is not engagable with said slide when
said slide is disposed in said second position and said balancing pocket
associated with said valve moves said first distance toward said at least
one base member during drum tilting, wherein said second actuating member
is engagable with said slide when said slide is disposed in said second
position and said balancing pocket associated with said valve moves a
second distance away from said at least one base member during drum
tilting, and wherein said second actuating member is not engagable with
said slide when said slide is disposed in said first position and said
balancing pocket associated with said valve moves said second distance
away from said at least one base member during drum tilting.
8. The combination of claim 7 wherein said first actuating members are
disposed on valve shafts, and wherein said plurality of valves further
comprise levers for transforming motion of said first actuating members
during engagement with said slides.
9. The combination of claim 7 wherein said at least one base member
comprises a rigid drive plate.
10. The combination of claim 7 wherein said plurality of valve selector
slides are radially shiftable between said first and second positions.
11. The combination of claim 10 further comprising means for shifting said
plurality of valve selector slides from said first positions to said
second positions, said shifting means comprising a collar axially slidable
on said drive shaft and connected by linkages to said slides.
12. The combination of claim 4 wherein said laundry machine further
comprises a plurality of drive lugs fixed to said drum and axially
extending through said at least one valve actuator.
13. The combination of claim 12 further comprising switch means actuated by
said drive lugs for use in controlling rotation of said rotatable drum.
14. The combination of claim 12 wherein said laundry machine further
comprises pads mounted on said drive lugs to contact said at least one
valve actuator and limit drum tilting.
15. The combination of claim 4 wherein said at least one fluid supplier
comprises a 360.degree. self contained fluid tank mounted for rotation
with said drum.
16. The combination of claim 4 wherein said at least one fluid supplier
comprises a 360.degree. fluid supply ring, mounted for rotation with the
drum, and a conduit connected to a fluid source for introducing fluid into
said fluid supply ring.
17. The combination of claim 4 wherein said plurality of balancing pockets
comprises a plurality of baffle tanks positioned within said rotatable
drum.
18. The combination of claim 4 wherein said plurality of balancing pockets
comprises three balancing pockets spaced about 120.degree. apart.
19. A laundry apparatus comprising:
a rotatable drum;
a motor powered drive shaft driving the rotation of said rotatable drum;
resilient means for mounting said rotatable drum to said drive shaft to
allow limited tilting of said rotatable drum relative to an axis of
rotation of said drive shaft;
valve actuator means corotatably mounted to said drive shaft;
a plurality of balancing pockets disposed around the drum for receiving
fluid to counterbalance an unbalanced load in the rotatable drum tending
to tilt the drum during drum rotation;
a plurality of fluid passages for communicating fluid to said plurality of
balancing pockets;
means for supplying fluid to said fluid passages; and
valve means for operatively engaging said valve actuator means during drum
tilting to selectively open said plurality of fluid passages to permit
fluid flow from said fluid supplying means into said plurality of
balancing pockets to counterbalance the unbalanced load in said rotatable
drum.
20. The combination of claim 19 wherein said valve means comprises first
means for opening said fluid passages when said rotatable drum rotates
below a predetermined speed and second means for opening said fluid
passages when said rotatable drum rotates above said predetermined speed.
21. The combination of claim 19 wherein said valve actuator means comprises
a plurality of slider means shiftable between first and second positions,
said slider means operatively engagable with said first means of said
valve means only when disposed in said first position, said slider means
operatively engagable with said second means of said valve means only when
disposed in said second position.
Description
BACKGROUND OF THE INVENTION
The present invention pertains to an apparatus for counterbalancing
unsymmetrically distributed centrifugal forces in a rotating body, and, in
particular, to a balancing apparatus for counterbalancing an unbalanced
batch of laundry being rotated at high speeds within a laundry machine for
purposes of water extraction.
In contemporary laundry appliances, such as automatic washing machines and
dryers, wherein clothes are washed and centrifuged in the washer and then
transferred to the dryer for clothes drying, or in combination
washer-dryers wherein clothes are washed, rinsed, spun dry and tumbled dry
with the application of heat energy, the drying time required to dry the
clothes is dependent on several factors, including the applied heat and
the amount of moisture retained in the clothes at the commencement of the
drying cycle. When washers are used without a complementary dryer and the
washed clothes are line dried, the amount of moisture similarly impacts
drying time. Thus, in order to reduce the drying time, the excess moisture
of the clothes is desirably reduced before the drying cycle.
One technique frequently employed to extract water from the clothes is to
provide a high rotating drum speed during the extraction part of the wash
cycle to remove large amounts of water from the load prior to its tumble
or line drying. One problem with such a spinning technique is that when a
load or batch of clothes is introduced into the clothes basket or
cylinder, the load is frequently distributed in such a manner that the
center of mass of the loaded cylinder will not coincide with the cylinder
axis, thereby producing an unbalanced centrifugal force which is directly
proportional to the mass of the unbalanced portion of the total rotating
mass, the square of the angular velocity of such unbalanced mass and the
radius of the unbalanced mass from the axis of rotation of the cylinder.
Besides affecting the power input required to rotate the cylinder, an
unbalanced condition may cause serious vibrations during cylinder
rotation. The vibrations may be sufficiently great to actually cause the
laundry machine to lift from its support and produce a violent movement of
the machine which is colloquially referred to as "walking".
To overcome these vibrational problems, previous laundry machines have
employed a variety of tactics. For instance, some laundry machines operate
at a sufficiently limited spin speed such that the unbalanced loads
typically encountered during operation are insufficient to produce a
sufficient amount of centrifugal force to lift the machine form its
support and produce "walking" of the machine. Other machines reduce spin
speeds upon sensing a severe vibration occurrence. While useful to some
extent, these devices have the disadvantage of slowing the overall drying
process as the rate at which water is extracted during the period of time
in which they are operating is less than desired. Extra moisture retained
in the clothes is therefore required to be removed either by a longer
period of line drying or by additional consumption of heat energy in
machine drying as a longer drying period is necessitated.
Other balancing mechanisms have suspended the entire laundry mechanism on a
pivot along with an additional mass producing, dead weight within the
enclosing cabinet on a complex spring system. The suspended system is
permitted to vibrate within the cabinet in which it is enclosed, and the
dead weight tends to reduce undesirable effects of the unbalanced
centrifugal forces. A shortcoming of these designs is that, to accommodate
the vibratory motion, the size of the clothes basket must be smaller for a
given size cabinet, thereby reducing washer capacity.
Another technique for overcoming vibration tendencies of an eccentric
loading within a rotating clothes basket is to selectively fill tanks
provided around the periphery of the clothes basket with fluid to
counterbalance the eccentric mass during certain portions of the rotation
of the clothes basket. An assortment of devices intended to realize this
technique are known, and representative devices are disclosed in U.S. Pat.
Nos. 2,886,979, 3,119,773, 3,135,688, 3,190,447, 3,306,453 and 3,983,035.
While perhaps having some utility to overcome vibrational problems, these
devices are not without their shortcomings.
For example, while many prior art washers with balancing pockets perform
balancing of the unbalanced load after a critical speed of the washer has
been reached, for rotational speeds above a one gravity (one G) producing
speed and below the critical speed, no balancing is performed. However,
significant vibrations, especially with heavy loads such as blankets or
pillows, are likely to occur at below critical speed. Consequently, the
designers of these washers typically resorted to providing bulky dampening
devices and an appreciable space between the wash tub and cabinet to allow
for the vibrational movements or oscillations of the clothes basket and
tub assembly caused by unsymmetrical centrifugal forces produced at below
critical speed. These spaces undesirably increased the size of the washing
machine or necessitated a smaller capacity clothes basket be used.
Another shortcoming of the prior art is that the components used to
selectively introduce water into the appropriate balancing pockets are
frequently complicated in design and assembly. As a result, installation
and maintenance of the balancing apparatus may be time consuming and
expensive.
Thus, it is desirable to provide a balancing system for a rotating
apparatus which overcomes these and other shortcomings of the prior art.
SUMMARY OF THE INVENTION
The balancing apparatus of the present invention counterbalances unbalanced
loads in rotating drums, such as clothes baskets in washing machines, to
prevent the rotating unbalanced loads from generating undesirable levels
of vibration. The balancing apparatus may also be configured to
advantageously function both below and above the critical speed of the
loaded rotating drum.
In one form thereof, the present invention provides a balancing apparatus
for a centrifugal extractor machine including a rotatable drum mounted on
a shaft, wherein the drum is tiltable relative to the shaft whereby the
axis of rotation of the drum is angled relative to an axial direction in
which the shaft extends. The balancing apparatus includes at least one
valve actuator arranged around the shaft, a plurality of balancing pockets
disposed around the drum for receiving fluid to counterbalance an
unbalanced load in the rotatable drum tending to tilt the drum during drum
rotation, a plurality of fluid passages for communicating fluid to the
plurality of balancing pockets, at least one fluid supplier providing
fluid to the plurality of fluid passages, and a plurality of valves
controlling fluid flow through the plurality of fluid passages. The
plurality of valves are each designed to operatively engage the valve
actuator when the balancing pocket to which its respective valve passage
communicates moves a certain distance toward the valve actuator during
drum tilting, and engagement of each valve with the valve actuator opens
the valve to allow fluid from the fluid supplier to flow through the fluid
passage associated with the open valve and into the balancing pocket
associated with the open valve to counterbalance the unbalanced load.
In another form thereof, the present invention provides, in combination, a
laundry machine and a balancing apparatus. The laundry machine includes a
rotatable drum and a motor powered drive shaft for rotatably driving the
rotatable drum, wherein the drum is tiltable relative to the drive shaft
whereby an axis of rotation of the drum is angled relative to an axial
direction in which the drive shaft extends. The balancing apparatus, which
counterbalances an unbalanced load in the rotatable drum, includes at
least one valve actuator corotatable with the drive shaft, a plurality of
balancing pockets disposed around the drum for receiving fluid to
counterbalance the unbalanced load in the rotatable drum tending to tilt
the drum during drum rotation, a plurality of fluid passages for
communicating fluid to the plurality of balancing pockets, at least one
fluid supplier providing fluid to the plurality of fluid passages, and a
plurality of valves controlling fluid flow through the fluid passages.
Each valve is structured and arranged to operatively engage the valve
actuator when the balancing pocket to which its respective valve passage
communicates moves a first distance toward the valve actuator during drum
tilting. Engagement of each valve with the valve actuator opens the valve
to allow fluid from the fluid supplier to flow through the fluid passage
and into the balancing pocket associated with the open valve to
counterbalance the unbalanced load.
In still another form thereof, the present invention provides a laundry
apparatus including a rotatable drum, a motor powered drive shaft for
rotatably driving the rotatable drum, resilient means for mounting the
rotatable drum to the drive shaft to allow limited tilting of the
rotatable drum relative to an axis of rotation of the drive shaft, valve
actuator means corotatably mounted to the drive shaft, a plurality of
balancing pockets disposed around the drum for receiving fluid to
counterbalance an unbalanced load in the rotatable drum tending to tilt
the drum during drum rotation, a plurality of fluid passages for
communicating fluid to the plurality of balancing pockets, means for
supplying fluid to the fluid passages, and valve means for operatively
engaging the valve actuator means during drum tilting to selectively open
the plurality of fluid passages to permit fluid flow from the fluid
supplying means into the plurality of balancing pockets to counterbalance
the unbalanced load in the rotatable drum.
One advantage of the present invention is that it counterbalances an
unbalanced load in a rotating drum both above and below a critical speed
of the rotating drum.
Another advantage of the present invention is that it may be employed with
both vertical axis and horizontal axis laundry appliances.
Another advantage of the present invention is that the water supply for a
balancing apparatus employing fluid receiving balance tanks may be
positioned adjacent the balance tanks.
Another advantage of the present invention is that by positioning the
valves and water supply to the balance tanks in close proximity to the
tanks, a fast delivery of counterbalancing water is achieved.
Another advantage of the present invention is that it limits the need for
the conventional suspensions, snubbers, pivots, and dead weights typically
provided in laundry appliances to allow clothes baskets to pass through
their critical speeds.
Still another advantage of the present invention is that by balancing the
clothes basket below a critical speed the invention allows smaller
clearances to be designed between the wash tub and the laundry machine
cabinet.
Still another advantage of the present invention is that mounting the
valves for direct activation allows for a proportional valve opening and
permitting the valves to remain continuously open until the balancing is
complete.
Still another advantage of the present invention is that freely available
centrifugal force is utilized to feed water to the balance tanks.
Still another advantage of the present invention is that the fluid
receiving tanks do not rely on oscillating components to deliver water but
rather are provided with water by valves which are actuated by direct
engagement with other balancing apparatus components.
BRIEF DESCRIPTION OF THE DRAWINGS
The above mentioned and other advantages and objects of this invention, and
the manner of attaining them, will become more apparent and the invention
itself will be better understood by reference to the following description
of embodiments of the invention taken in conjunction with the accompanying
drawings, wherein:
FIG. 1 is a side view in partial cross section and partially in
diagrammatic form of an embodiment of the balancing apparatus of the
present invention installed in a horizontal axis laundry appliance;
FIG. 2 is an enlarged view from FIG. 1 further illustrating the
construction of a valve and valve selector of the balancing apparatus;
FIG. 3 is a diagrammatic view illustrating the direction in which the
clothes basket tends to tilt relative to an unbalanced load when the
clothes basket rotates below a washer critical speed;
FIG. 4 is a diagrammatic view illustrating the direction in which the
clothes basket tends to tilt relative to an unbalanced load when the
clothes basket rotates above a washer critical speed; and
FIG. 5 is fragmentary, vertical sectional view of another embodiment of the
balancing apparatus of the present invention installed in a vertical axis
laundry appliance.
Corresponding reference characters indicate corresponding parts throughout
the several views. Although the drawings represent embodiments of the
invention, the drawings are not necessarily to scale and certain features
may be exaggerated or omitted in order to better illustrate and explain
the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, there is shown a laundry appliance, namely a
washing machine, with a balancing apparatus according to the principles of
the present invention. In FIG. 1, a pertinent, fragmentary portion of the
laundry appliance is shown in vertical cross-sectional side view. Certain
structural portions of the remainder of the laundry appliance which may be
of any suitable type known in the art have been abstractly shown or
omitted in the interest of clarity of illustration, and further because
the construction of such portions are not essential to an understanding of
the present invention. Although shown and described herein with reference
to a washer, it will be appreciated that this usage is merely illustrative
of the present invention and not intended to be limiting. The balancing
apparatus of the invention can be advantageously incorporated into a
variety of devices, such as a combination washer/dryer, in which
centrifugal force is used to extract liquid from materials within a
rotating drum and in which vibrational forces resulting from an eccentric
arrangement of the materials within the drum is desired to be reduced, or
industrial extractors for other uses.
The washing machine is generally designated 10 and is a front-loading,
horizontal clothes basket axis type machine. Washer 10 includes an
external cabinet or housing abstractly shown at 12 in which is fixedly
mounted stationery wash tub 14. Wash tub 14 includes a front opening 15
through which clothes or other materials to be washed may be inserted into
and withdrawn from a clothes basket or washing drum, generally designated
18.
Clothes basket 18, which is rotatably mounted within wash tub 14, is
cylindrically shaped and includes perforations (not shown) allowing liquid
to flow under centrifugal force radially therefrom. Three axially
elongated and radially inwardly projecting baffles 24 used to tumble
clothes during a wash cycle are mounted 120.degree. apart within basket 18
and each include an interior compartment 26 which serves as a liquid
receiving pocket. When selectively filled with liquid as described further
below, pockets or tanks 26 counterbalance an unbalanced load indicated at
20 to limit undesirable vibrations of the washer.
Clothes basket 18 is mounted to a reduced diameter portion of drive shaft
28. Annular rib 19 provided on the clothes basket hub is captured between
a pair of resilient bushings 30 and a pair of washers 32 secured around
drive shaft 28. The section of drive shaft 28 axially extending through
wash tub 14 is connected with a not shown pulley system to a schematically
shown motor 34 that powers the drive shaft rotation that effects rotation
of clothes basket 18. A bearing mounting of drive shaft 28 and an
appropriate seal around drive shaft 28 preventing moisture from escaping
from wash tub 14 are not shown but are provided in a conventional fashion.
Secured for rotation on the rear wall of clothes basket 18 is a fluid
distribution ring 36, preferably made from molded plastic. Ring 36 is a
continuous, unsegmented ring into which fluid such as water may be
introduced during balancing operations through a hose 38 in flow
communication with a water source (not shown). When clothes basket 18
spins during extraction of material therein, fluid within ring 36 collects
as shown at 40 under the influence of centrifugal force. Due to the
unsegmented construction of ring 36, fluid anywhere around the full
circular extent of ring 36 can pass into any of the liquid receiving
pockets 26 if necessary to balance the system. In an alternate embodiment,
hose 38 may be attached to a sump pump mounted within wash tub 14 to
recirculate water collected therein.
In order to control the flow of fluid into pockets 26, valves, generally
designated 42, are provided which open and close passages between pocket
26 and fluid 40 within fluid distribution ring 36. In the shown
embodiment, these fluid passages comprise openings 44 formed into the rear
wall of clothes basket 18. Although only one valve 42 is shown, three
similar valves 42 spaced at 120.degree. intervals to be aligned with
baffle tanks 26 are preferably provided.
Referring now to FIG. 2, which is an enlarged portion of FIG. 1, valve 42
includes a body section 43 pivotally mounted to axially extending ears 48
fixedly attached to clothes basket 18. A valve seat 50, made of a
resilient material such as neoprene, seals passage 44 when disposed in the
Shown position. Valve 42 also includes a first actuating arm 52 and a
second, hook shaped actuating arm 54. A recess 53 formed into the clothes
basket rear wall may be provided to accommodate pivoting motion of
actuating arm 52. While in the shown embodiment valve 42 is maintained in
the shown position by the centrifugal forces acting thereupon, a spring
(not shown) may also be provided to positively force valve 42 to the
closed position.
In an alternate embodiment, valves 42 can be mounted to ears of a forward,
annular flange which is integrally molded with plastic ring 36. Associated
valve springs may be mounted between the valves and the forward flange.
The forward flange, which would include the fluid passages 44 molded
therein, would then be installed to the basket rear wall in a convenient
fashion to facilitate assembly.
Referring again to FIG. 1, axially arranged on drive shaft 28 is an
assembly which serves as a valve actuator for this embodiment. A rigid,
disc shaped drive plate 58 made of steel or other suitable material is
welded or otherwise rigidly secured to drive shaft 28 so as to rotate with
shaft 28. Drive plate 58 provides a fixed reference from which deflection
of basket 18 can be measured. Instead of a single drive disc, alternative
components, for example a one-piece or multiple piece three-pronged spider
having legs aligned with valves 42, could be substituted within the scope
of the invention. Slidably mounted in radially oriented slots formed in
the radial periphery of drive plate 58 are valve selector slides 60. While
one slide is shown, three similar slides 60 spaced 120.degree. apart and
in registry with valves 42 for operative engagement therewith are arranged
on drive plate 58. Slide 60 includes lugs 62, 64 on its forward and
rearward faces respectively which are sized to abut and engage actuating
arms 52, 54 of valve 42 as described further below.
An ear 66 on each slide 60 is connected by link 68 to collar 70 used to
radially shift slides 60 between first and second positions. Annular
collar 70 is keyed to drive shaft 28 and is axially slidable therealong. A
biasing element such as helical spring 72 acting against washer 74 biases
collar 70 forward to the shown position. A solenoid assembly 76 which is
mounted externally of wash tub 14 to avoid being wetted operates an
L-shaped linkage 78 designed to engage annular shoulder 71 of collar 70.
When solenoid assembly 76 is energized, linkage 78 is pivoted to shift
collar 70 inwardly, thereby pulling slides 60 to their not shown radially
inward position, against the returning force of spring 72.
Fixedly mounted to clothes basket 18 at angular positions corresponding to
baffles 24 are three similarly configured drive pins 82. As shown in FIG.
1, drive pin 82 axially projects through an opening in drive plate 58.
This interconnection provides a positive drive mechanism between drive
plate 58 and clothes basket 18 such that basket 18 will rotate with drive
shaft 28 even if slippage were to otherwise occur between bushings 30 and
annular rib 19. The distal ends of drive pins 82 contact a ring-shaped
switch actuator 84 encircling shaft 28 which is spring biased forward into
engagement with pins 82. Upon axial movement of drive pins 82, actuator 84
axially moves such that actuator finger 85 operates a switching assembly,
abstractly shown at 87, connected to a not shown control mechanism to
regulate the operation of washer 10. Switch assembly 87 includes a water
supply switch and a motor speed hold or limit switch. Multiple fingers 85
are provided on actuator 84 to separately contact the various switches and
to properly assemble a 360.degree. switch actuator around the drive shaft.
A suitable not shown speed sensor monitors the rotational speed of drive
shaft 28 or basket 18, for example by sensing the speed of motor 34. Any
of a variety of speed sensors known in the art, for example a sensor which
magnetically or electronically senses motor speed, may be employed. Pads
89 around drive pin 82 serve as drum deflection or tilting limits by
abutting drive plate 58. As an electronic overload switch is preferably
incorporated into switching assembly 87 and circuited with the washer
control to stop basket spinning and to turn a red light on if basket
tilting exceeds a design limit, pads 89 are furnished to provide operating
range and noise reduction in achieving a mechanical fail safe device.
The construction of the balancing apparatus utilized with washer 10 will be
further understood in view of the following explanation of its operation.
After the wash cycle is completed in washer 10 and after the pump out of
the wash water from tub 14, a timer within the control mechanism switches
to the spin mode or extraction cycle which involves rotating or spinning
clothes basket 18 at high speeds in order to centrifugally force water
within the load of clothes or other items through the perforations in
basket 18 to partially dry the clothes. As rotation of basket 18 is
accelerated from a non-rotating condition by operation of motor 34,
rotational speeds are reached whereat a centrifugal force at the drum
interior walls equal to one gravity or more is produced, which causes
clothes to cling to the interior walls of clothes basket 18. One gravity
speeds are typically more than 50 rpms depending on basket 18 diameter. As
is known in the art, and as diagrammatically shown in FIG. 3, at speeds
between one gravity and a critical washer speed, unsymmetrical centrifugal
forces produced by the presence of eccentric or unbalanced loading tends
to cause basket 18 to tilt toward the unbalanced load 20. In other words,
the axis of rotation 22 of basket 18 is angularly shifted toward the
unbalanced load 20 relative to the axis of rotation of drive shaft 28. The
critical speed of rotating basket 18 is dependent on the basket diameter,
mass of clothes basket 18 and the clothes load. In the shown embodiment,
bushings 30 are particularly designed to permit such tilting in a
controlled manner. The amount of tilting, is modified by controlling the
durometer of the resilient bushings 30 and the spacing between the washers
32.
As basket rotation continues to accelerate and reaches and passes the
critical speed, the tilting of basket 18 shifts 180.degree.. As shown in
the diagrammatic view of FIG. 4, above the critical speed basket 18 tilts
away from the unbalanced load 20. However, both below and above the
critical speed, balancing of the unbalanced load 20 requires introduction
into one, and possibly two, of the fluid pockets 26 most diametrically
opposed to load 20.
Initially during the water extraction cycle, valve selector slides 60 are
situated in the radially outward position shown in FIG. 1. At tumble speed
and spinning speeds above the one gravity speed and below the critical
speed, the unbalanced load 20 causes the bottom part of the basket 18
shown in FIG. 1 to float or tilt toward drive plate 58 and the upper part
of the basket 18 in FIG. 1 to move away from drive plate 58. As basket 18
tilts, drive pins 82 axially move fingers 85 of ring switch actuator 84 to
first actuate the water supply switch and then activate the motor speed
limit switch in switching assembly 87. Specifically, activation of the
water supply switch causes water to be introduced through hose 38 into
distribution ring 36. And, if the basket 18 has tilted to the end of its
operating range, the motor speed limit switch is activated and the
acceleration of motor 34 is stopped such that motor 34 holds its speed to
allow the balancing apparatus time to balance basket 18.
In particular, during tilting movement of the basket 18, the valve arm 54
illustrated in FIG. 1 directly engages lug 64 to lift valve seat 50 and
open passage 44. It will be appreciated that because at this point in the
extraction cycle lugs 62 on slides 60 are not aligned with valve arms 52,
the valve 42 disposed most proximate to unbalanced load 20 will not be
opened when that valve simultaneously moves toward the valve actuator
during drum tilting. As a result, water will not be added to baffle tank
26 proximate load 20 to compound the tilting. When load 20 is located in
line or near a baffle tank 26, two valves 412 may be brought into
engagement with the valve actuator simultaneously to be opened thereby.
Water 40 introduced into ring 36 continuously pours through opened passage
44 to fill baffle tank 26 with enough water to even out the load, which in
turn lessens drum tilting such that valve 42 disengages slide 60 and
centrifugal force shifts valve seat 50 to close passage 44. If sufficient
balancing has not been reached within a certain time limit after the motor
acceleration has been halted and within a preselected preprogrammed
maximum time allowed for the spin duration, a condition which may occur
when, for example, the baffle tanks 26 are already filled, the washer
control is preferably programmed to activate a spin recycling switch. The
recycling switch causes the water supply to be turned off and the motor
speed to be reduced such that the clothes are tumbled and baffle tanks 26
are emptied and to redistribute the load, and a second try is then made to
reach the maximum spin speed. The water in tanks 26 is emptied
automatically through ports (not shown) provided in the radially inner
portion of tanks 26 when the basket rotating speed provides less than one
gravity of centrifugal force. Water 40 falls from distribution ring 36
down into tub 14 during decelerating rotation of basket 18. If balancing
occurs within the time limit, the basket 18 continues to be accelerated up
to the critical speed. During this acceleration the weight distribution of
unbalanced load 20 may shift, and therefore the balancing apparatus
continues to counterbalance any further or different tiltings of basket 18
in the above described manner.
When the rotation of basket 18 reaches a predetermined critical speed as
sensed by the speed sensor, the washer control energizes solenoid assembly
76 to move collar 70 and shift slides 60 into a second position for
correct water distribution to the proper baffle tanks 26. The slide
shifting to the second position need not occur precisely at the critical
speed but rather may be performed within a speed range around the critical
speed for the washer determined through tests to suit various clothes
loads. At this position, slide lugs 62 are disposed for engagement with
valve arms 52, and slide lugs 64 are not engagable with valve arms 54.
When basket 18 then tips sufficiently in a direction opposite unbalanced
load 20, drive pins 82 again serve to restart water introduction into
distribution ring 36 through hose 38 and halt motor acceleration, and the
valve arm 52 on the valve 42 opposite the load is brought into abutting
contact with lug 62 to open the valve and allow water 40 through passage
44 into baffle tank 26 to balance the load in a similar manner as
described above. Counterbalancing continues in this manner until the
extraction cycle is complete, at which time the basket comes back to
tumbling speed to fluff the clothes and empty the baffles before stopping.
The above embodiment can be modified in a variety of respects within the
scope of the invention. For example, if counterbalancing is only to be
performed above a critical speed, slide 60 can be eliminated and valve
arms 52 could directly abut drive plate 58. Rather than the gate-like
configuration shown, passages 44 Could be elongated tubes if spacing
between baffle pockets 26 and distribution ring 36 is required. In
addition, although not preferred as construction would be more
complicated, separate hoses connected to a fluid source could be
separately routed to the several valves 42 to individually introduce water
to passages 44.
Referring now to FIG. 5, there is shown a fragmentary, vertical
cross-sectional view of selected portions of another laundry appliance in
which is installed a second embodiment of a balancing apparatus of the
present invention which functions in a conceptually similar fashion to the
embodiment described above. The shown laundry appliance, which is a
vertical axis washing machine well known in the art, is generally
designated 100 and includes a perforated, cylindrical clothes basket 102
in which an unbalanced batch of laundry is shown at 104. Clothes basket
102 is mounted via a resilient bushing 106 to a drive shaft 108 rotatably
powered by a not shown motor. Agitator 110 is moved or oscillated within
clothes basket 102 during the wash cycle by a motor powered drive shaft
112 axially extending through a bushing lined bore through drive shaft
108.
Fixedly secured to drive shaft 108 for rotation therewith is disc shaped
drive plate 114. While only one is shown, three radially shiftable valve
selector slides 118 spaced at 120.degree. angular intervals are slidably
mounted to drive plate 114. Each slide 118 includes a below critical speed
lug 120 and an above Critical speed lug 122. The assembly used to shift
slides 118 from the below basket critical speed arrangement shown to the
radially inward, above basket critical speed arrangement is similarly
configured to the embodiment of FIG. 1 and not shown for purposes of
clarity of illustration. Spaced at 120.degree. intervals are three drive
lugs 116 provided with basket deflection limit pads 124. Drive lugs 116
are secured to the underside of clothes basket 102 and extend through
holes in drive plate 114 for a positive drive engagement. A suitable ring
switch actuator and associated switch and control means which the distal
end of drive lugs 116 triggers during basket tilting is similar to the
FIG. 1 configuration and is not shown.
Secured to the underside of clothes basket 102 is a self contained fluid
tank 126 filled with fluid such as water which is not emptied during use
so as to be reusable with subsequent washing loads. Fluid tank 126 is
annular shape and its interior compartment is unsegmented along its entire
360.degree. circumference such that water at any point of tank 126 can
move to the appropriate balance tank 128. Upwardly extending from tank 126
is shown a sector balance tank or liquid receiving pocket 128. Three
similarly constructed balance tanks 128 spaced at 120.degree. intervals
are preferably arranged on the outer periphery of clothes basket 102 and
selectively filled with liquid to counterbalance unbalanced load 104. A
top or barrier wall 130 of fluid supply tank 126 separating balance tank
128 from fluid supply tank 126 includes an inlet passage 132, and a vent
and drain passage 134 near the inner radial portion of tank 126.
Inlet passage 132 is opened and closed to regulate the flow of fluid from
fluid supply tank 126 into balance tank 128 by a push/pull valve generally
designated 136. One valve 136 is preferably provided for each balance tank
128. Valve 136 includes a resilient valve seat 138 mounted on the distal
end of valve shaft or rod 140. Actuating arms 142, 144 radially extend
from rod 140. Activating arm 144 engages slide lug 120. Actuating arm 142
engages slide lug 122 via lever 146, which is pivotally mounted to fluid
supply tank 126 and serves to transform axial motion of arm 142 as
described below. Rod 140 extends through a plug assembly 148 inserted into
fluid tank 126 that houses O-ring seal 149 to prevent fluid within tank
126 from leaking. Spring 151 biases valve seat 138 into sealing engagement
with inlet passage 132.
The construction of this embodiment will be further understood in view of
the following general explanation of its operation. It will be appreciated
by those of ordinary skill in the art that the overall operation is
similar to the operation of the embodiment of FIG. 1, and therefore the
explanation of its operation will be more limited. During the spin cycle
and when clothes basket 102 is rotating above a one gravity speed but
below a critical speed, when the unbalanced load 104 is positioned as
shown, clothes basket 102 will tilt relative to drive shaft 108 toward the
right in FIG. 5. When tilted sufficiently, valve actuating arm 144 will
abut slide lug 120. Upon further tilting of clothes basket 102, barrier
wall 130 moves away from valve 136 to unseat valve seat 138 and open inlet
passage 132. Water which fills the radially outward portions of fluid
supply tank 126 due to the centrifugal force produced by rotation passes
through inlet passage 132 to fill the appropriate sector balance tank 128
to counterbalance load 104. It will be appreciated that for the shown
position of load 104 diametrically opposite balance tank 128, the valves
136 associated with the not shown tanks 128 will not be opened when
barrier wall 130 moves axially toward drive plate 114 during basket
tilting as their respective actuating arms 142 will not engage lugs 122 as
the radially inward ends of their respective levers 146 are not aligned
with lugs 122.
During rotation above the critical speed, valve selector slides 118 will be
moved to a not shown, radially inward position whereby lugs 122 will be
aligned for engagement with the radially inward ends of levers 146. When
clothes basket 102 tilts to the left in FIG. 5, the inward leg of lever
146 contacts lug 122 and causes the outward leg of lever 146 to pivot
further downward and force actuating arm 142 downward. The increased or
magnified downward motion of arm 142 relative to fluid supply tank 126
unseats valve seat 138 and allows water in supply tank 126 to flow through
passage 132 into balance tank 128 for counterbalancing purposes. When
rotation is sufficiently slowed or stopped, water in balance tanks 128
automatically empty as water therein flows back by gravity to fluid supply
tank 126 through drain passages 134.
While this invention has been described as having multiple designs, the
present invention may be further modified within the spirit and scope of
this disclosure. This application is therefore intended to cover any
variations, uses, or adaptations of the invention using its general
principles. Further, this application is intended to cover such departures
from the present disclosure as come within known or customary practice in
the art to which this invention pertains.
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